Field of the Disclosure
The present disclosure relates to a fin structure for a heat exchanger for automotive applications, in particular for agricultural and on-site machines.
Description of the Related Art
The current brazed aluminium evaporators for automotive air-conditioning applications are designed for filtered environments, where the filtration is mainly intended to eliminate pollen or undesirable odours. In the case of off-road applications often the same evaporators developed for road applications are used. The latter, however, are unable to deal with the following problems: notable presence of pollutants (such as dust) which may easily clog the evaporator unit; and aggressive handling of the component, in particular during cleaning thereof. In the heat exchangers for off-road applications the unit may be cleaned by means of a brush or pressurised water and during such an operation it may happen that the component itself must be disassembled. In this case the fins may be damaged during handling of the component.
Some known evaporator configurations, which are provided with fins having louvering or undulations for increasing the turbulence of the air flow, and therefore increasing the heat exchange coefficients, are shown in FIGS. 1, 2a and 2b. 
The known evaporator shown in FIG. 1 comprises a plurality of heat transfer conduits 2, in particular plate-like conduits, which are arranged parallel to each other as flow paths for a heat exchange medium. Each plate-like conduit and the adjacent conduit have, arranged in between, a plurality of fin members 3 which include respective segments of a metal sheet 5 folded in wave form and brazed to the plate-like conduits between which it is arranged. In the example shown, the metal sheet is folded in a square wave form, but other configurations for folding the sheet are known, for example a sinusoidal, triangular or other wave form.
The fin members 3 are conventionally configured to provide an air inlet end 3a for air inflow, an air outlet end 3b for air outflow, and an air flow path 3c which connects the air inlet end 3a with the air outlet end 3b and allows a heat exchange with the plurality of heat transfer conduits 2. According to the known configuration shown in FIG. 2, which is common in braze-welded evaporators, the fin members 3 are also configured to have louvering, namely a series of slits with a folded edge, for determining a winding path with many leading edges able to create vortices and turbulence. This louvering favours, however, the accumulation of dirt on the fins.
Another known configuration able to increase the turbulence of the air flow, and therefore increase the heat exchange coefficient, is that shown in FIG. 2b; according to this configuration, the fin members 3 are configured to have undulations comprising undulation peaks 7 alternating with undulation troughs 9. The known undulation configuration shown in FIG. 2, however, does not allow efficient disposal of the condensate water which forms during operation of the exchanger and collects inside the undulation troughs 9 (indicated by the areas W in FIG. 2); the air which flows between the fins is in fact unable to push all the water beyond the undulation peaks 7 and therefore as far as the end of the fin on a front side of the evaporator. This water therefore stagnates inside the undulation troughs, mixing with the dust and dirt which in the long run may result in the formation of obstructions.
The document WO 2007/013623 describes a heat exchanger, the fins of which are provided with undulations; these undulations are configured to obtain given results in terms of fluid dynamics and heat exchange, but are unable to ensure efficient disposal of the condensate water.